kernel/vm: change pde table info from single buffer to explicit per-process.

makes code in kernel more readable, and allows better sanity checking on
using the pde info.

kernel/arch/i386/arch_do_vmctl.c

@@ -12,8 +12,6 @@
 
 #include "proto.h"
 
-extern u8_t *vm_pagedirs;
-
 /*===========================================================================*
  *				arch_do_vmctl				     *
  *===========================================================================*/
@@ -26,13 +24,15 @@ struct proc *p;
 		/* Get process CR3. */
 		m_ptr->SVMCTL_VALUE = p->p_seg.p_cr3;
 		return OK;
-	case VMCTL_I386_SETCR3:
+	case VMCTL_SETADDRSPACE:
 		/* Set process CR3. */
-		if(m_ptr->SVMCTL_VALUE) {
-			p->p_seg.p_cr3 = m_ptr->SVMCTL_VALUE;
+		if(m_ptr->SVMCTL_PTROOT) {
+			p->p_seg.p_cr3 = m_ptr->SVMCTL_PTROOT;
+			p->p_seg.p_cr3_v = (u32_t *) m_ptr->SVMCTL_PTROOT_V;
 			p->p_misc_flags |= MF_FULLVM;
 		} else {
 			p->p_seg.p_cr3 = 0;
+			p->p_seg.p_cr3_v = NULL;
 			p->p_misc_flags &= ~MF_FULLVM;
 		}
 		RTS_UNSET(p, RTS_VMINHIBIT);
@@ -48,11 +48,6 @@ struct proc *p;
 		r = prot_set_kern_seg_limit(m_ptr->SVMCTL_VALUE);
 		return r;
 	}
-	case VMCTL_I386_PAGEDIRS:
-	{
-		vm_pagedirs = (u8_t *) m_ptr->SVMCTL_VALUE;
-		return OK;
-	}
 	case VMCTL_I386_FREEPDE:
 	{
 		i386_freepde(m_ptr->SVMCTL_VALUE);

kernel/arch/i386/memory.c

@@ -28,12 +28,6 @@
 
 PRIVATE int psok = 0;
 
-#define PROCPDEPTR(pr, pi) ((u32_t *) ((u8_t *) vm_pagedirs +\
-				I386_PAGE_SIZE * pr->p_nr +	\
-				I386_VM_PT_ENT_SIZE * pi))
-
-PUBLIC u8_t *vm_pagedirs = NULL;
-
 #define MAX_FREEPDES (3 * CONFIG_MAX_CPUS)
 PRIVATE int nfreepdes = 0, freepdes[MAX_FREEPDES];
 
@@ -90,6 +84,7 @@ PRIVATE phys_bytes createpde(
 
 	assert(free_pde_idx >= 0 && free_pde_idx < nfreepdes);
 	pde = freepdes[free_pde_idx];
+	assert(pde >= 0 && pde < 1024);
 
 	if(pr && ((pr == ptproc) || !HASPT(pr))) {
 		/* Process memory is requested, and
@@ -106,7 +101,8 @@ PRIVATE phys_bytes createpde(
 		 * accessible directly. Grab the PDE entry of that process'
 		 * page table that corresponds to the requested address.
 		 */
-		pdeval = *PROCPDEPTR(pr, I386_VM_PDE(linaddr));
+		assert(pr->p_seg.p_cr3_v);
+		pdeval = pr->p_seg.p_cr3_v[I386_VM_PDE(linaddr)];
 	} else {
 		/* Requested address is physical. Make up the PDE entry. */
 		pdeval = (linaddr & I386_VM_ADDR_MASK_4MB) | 
@@ -118,8 +114,9 @@ PRIVATE phys_bytes createpde(
 	 * can access, into the currently loaded page table so it becomes
 	 * visible.
 	 */
-	if(*PROCPDEPTR(ptproc, pde) != pdeval) {
-		*PROCPDEPTR(ptproc, pde) = pdeval;
+	assert(ptproc->p_seg.p_cr3_v);
+	if(ptproc->p_seg.p_cr3_v[pde] != pdeval) {
+		ptproc->p_seg.p_cr3_v[pde] = pdeval;
 		*changed = 1;
 	}
 
@@ -155,6 +152,11 @@ PRIVATE int lin_lin_copy(const struct proc *srcproc, vir_bytes srclinaddr,
 
 	assert(procslot >= 0 && procslot < I386_VM_DIR_ENTRIES);
 
+	if(srcproc) assert(!RTS_ISSET(srcproc, RTS_SLOT_FREE));
+	if(dstproc) assert(!RTS_ISSET(dstproc, RTS_SLOT_FREE));
+	assert(!RTS_ISSET(ptproc, RTS_SLOT_FREE));
+	assert(ptproc->p_seg.p_cr3_v);
+
 	while(bytes > 0) {
 		phys_bytes srcptr, dstptr;
 		vir_bytes chunk = bytes;
@@ -191,6 +193,11 @@ PRIVATE int lin_lin_copy(const struct proc *srcproc, vir_bytes srclinaddr,
 		dstlinaddr += chunk;
 	}
 
+	if(srcproc) assert(!RTS_ISSET(srcproc, RTS_SLOT_FREE));
+	if(dstproc) assert(!RTS_ISSET(dstproc, RTS_SLOT_FREE));
+	assert(!RTS_ISSET(ptproc, RTS_SLOT_FREE));
+	assert(ptproc->p_seg.p_cr3_v);
+
 	return OK;
 }
 
@@ -677,6 +684,8 @@ int vm_phys_memset(phys_bytes ph, const u8_t c, phys_bytes bytes)
 
 	assert(nfreepdes >= 3);
 
+	assert(ptproc->p_seg.p_cr3_v);
+
 	/* With VM, we have to map in the physical memory. 
 	 * We can do this 4MB at a time.
 	 */
@@ -695,6 +704,7 @@ int vm_phys_memset(phys_bytes ph, const u8_t c, phys_bytes bytes)
 		ph += chunk;
 	}
 
+	assert(ptproc->p_seg.p_cr3_v);
 
 	return OK;
 }
@@ -1004,3 +1014,8 @@ PUBLIC int arch_enable_paging(struct proc * caller, const message * m_ptr)
 
 	return OK;
 }
+
+PUBLIC void release_address_space(struct proc *pr)
+{
+	pr->p_seg.p_cr3_v = NULL;
+}

kernel/arch/i386/sconst.h

@@ -30,7 +30,8 @@
 	FP_SAVE_AREA_P = P_STACKTOP
 	P_LDT_SEL = FP_SAVE_AREA_P + 532
 	P_CR3 = P_LDT_SEL+W
-	P_LDT = P_CR3+W
+	P_CR3_V = P_CR3+4
+	P_LDT = P_CR3_V+W
 	P_MISC_FLAGS = P_LDT + 50
 	Msize = 9	/* size of a message in 32-bit words*/
 

kernel/proto.h

@@ -182,4 +182,5 @@ _PROTOTYPE( int copy_msg_from_user, (struct proc * p, message * user_mbuf,
 _PROTOTYPE( int copy_msg_to_user, (struct proc * p, message * src,
 							message * user_mbuf));
 _PROTOTYPE(void switch_address_space, (struct proc * p));
+_PROTOTYPE(void release_address_space, (struct proc *pr));
 #endif /* PROTO_H */

kernel/system/do_clear.c

@@ -31,6 +31,8 @@ PUBLIC int do_clear(struct proc * caller, message * m_ptr)
   }
   rc = proc_addr(exit_p);	/* clean up */
 
+  release_address_space(rc);
+
   /* Don't clear if already cleared. */
   if(isemptyp(rc)) return OK;
 

kernel/system/do_fork.c

@@ -117,6 +117,9 @@ PUBLIC int do_fork(struct proc * caller, message * m_ptr)
   RTS_UNSET(rpc, (RTS_SIGNALED | RTS_SIG_PENDING | RTS_P_STOP));
   sigemptyset(&rpc->p_pending);
 
+  rpc->p_seg.p_cr3 = 0;
+  rpc->p_seg.p_cr3_v = NULL;
+
   return r;
 }